convince-project · ste93 · Jan 19, 2026 · Jan 13, 2026
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+# Changelog - fbrand-new Contributions to model2code
+
+## Executive Summary
+
+These contributions focused on **stabilizing and improving the code generation pipeline** for the model2code project. The main areas of improvement include:
+
+1. **Type System Improvements** - Better handling of data types from SCXML datamodels
+2. **Service/Topic Parsing** - Fixed parsing of ROS service and topic names  
+3. **Template Generation** - Improved skill template generation for ROS2
+4. **Stability Fixes** - Prevented crashes and incorrect code output
+
+---
+
+## Detailed Changes
+
+### 1. Response Field Type Handling
+
+**Commit:** `4cb8a93`
+
+#### Problem
+Generated code was not accounting for the actual field types in service responses. All fields were treated as strings, causing compilation errors for non-string types.
+
+#### Solution
+Added interface file parsing and type-aware code generation.
+
+**Updated code generation** in `src/Replacer.cpp`:
+```cpp
+// Create the appropriate field access expression based on type
+std::string fieldAccess;
+if (fieldType == "string") {
+    fieldAccess = "response->" + fieldName + ".c_str()";  // String needs c_str()
+} else {
+    fieldAccess = "response->" + fieldName;  // Other types used directly
+}
+```
+
+In order to get the correct type we need to somehow extract it from the files we have which leads us to:
+
+---
+
+### 2. Data Type Mapping via SCXML Location Attribute
+
+**Commit:** `3b1862b`
+
+#### Problem
+The code generator was unable to correctly map response field types from service interfaces to the appropriate datamodel variables, causing type mismatches in generated code.
+
+#### Solution
+Implemented a new mapping system that extracts data types from the SCXML datamodel by using the `location` attribute in `<assign>` tags.
+
+Let's take as an example the [IsCheckingForPeopleSkill](https://github.com/convince-project/UC3/blob/main/model-high-level/Skills/IsCheckingForPeopleSkill.scxml): 
+
+For example, at line [31-37](https://github.com/convince-project/UC3/blob/main/model-high-level/Skills/IsCheckingForPeopleSkill.scxml#L31-L37) we have an `assign` tag inside the `ros_service_handle_response`
+```
+<state id="query">
+<ros_service_handle_response name="/BlackboardComponent/GetInt" target="evaluate">
+    <assign location="m_value"  expr="_res.value"/>
+    <!-- Fix: Use is_ok instead of non-existent result field -->
+    <assign location="m_result" expr="_res.is_ok"/>
+</ros_service_handle_response>
+</state>
+```
+
+From the same file we then lookup for the `m_value` and `m_result` field in the datamodel to extract their
+types.
+
+[Lines 9-15](https://github.com/convince-project/UC3/blob/main/model-high-level/Skills/IsCheckingForPeopleSkill.scxml#L9C1-L15C15)
+```
+<datamodel>
+    <data id="m_name"         type="string"  expr="'isCheckingForPeople'"/>
+    <data id="m_value"        type="int32"   expr="0"/>
+    <data id="m_result"       type="bool"    expr="false"/>
+    <data id="SKILL_SUCCESS"  type="int8"    expr="0"/>
+    <data id="SKILL_FAILURE"  type="int8"    expr="1"/>
+</datamodel>
+```
+
+#### Code Changes
+
+**New data structure** in `include/Data.h`:
+```cpp
+// Added to eventDataStr struct (line 84)
+std::map<std::string, std::string> responseFieldToDatamodelMap;
+// Mapping from response fields to datamodel variables (e.g., "param" -> "m_param")
+```
+
+**New function** in `include/ExtractFromXML.h`:
+```cpp
+bool getInterfaceFieldsFromAssignTag(
+    tinyxml2::XMLElement* element, 
+    std::vector<std::string>& interfaceFields, 
+    std::map<std::string, std::string>& responseFieldToDatamodelMap
+);
+```
+
+**Core logic** in `src/ExtractFromXML.cpp` (lines 370-406):
+```cpp
+// Extract response field name from expr (e.g., "_res.param" -> "param")
+std::string exprStr(expr);
+size_t dotPos = exprStr.find('.');
+if (dotPos != std::string::npos) {
+    std::string responseField = exprStr.substr(dotPos + 1);
+    std::string datamodelVar(location);
+
+    // Store the mapping from response field to datamodel variable
+    responseFieldToDatamodelMap[responseField] = datamodelVar;
+    interfaceFields.push_back(responseField);
+}
+```
+
+**Updated replacer logic** in `src/Replacer.cpp` (lines 262-280):
+```cpp
+// Look up the datamodel variable for this response field
+std::string datamodelVar;
+auto mappingIt = eventData.responseFieldToDatamodelMap.find(responseField);
+if (mappingIt != eventData.responseFieldToDatamodelMap.end()) {
+    datamodelVar = mappingIt->second;
+} else {
+    // Fallback to the old logic if mapping is not found
+    datamodelVar = "m_" + fieldName;
+}
+
+// Get the type from interfaceData using the datamodel variable name
+auto pos = eventData.interfaceData.find(datamodelVar);
+```
+
+---
+
+### 3. Service Client Initialization in Skill Start
+
+**Commits:** `f0ad936`, `d24bc2b` | **Dates:** 2025-11-24, 2025-11-25 | **Type:** ARCHITECTURAL FIX
+
+#### Problem
+Service clients were being created inside the event callback lambda, causing repeated client creation on every event hence slowing down the whole application
+
+#### Solution
+Moved service client creation to the `start()` method, with proper service availability checking at startup.
+
+#### Code Changes
+
+**New member declarations** in `template_skill/include/TemplateSkill.h`:
+```cpp
+/*SERVICE_CLIENTS_LIST*//*SERVICE_CLIENT*/
+std::shared_ptr<rclcpp::Node> $eventData.nodeName$;
+std::shared_ptr<rclcpp::Client<$eventData.interfaceName$::srv::$eventData.functionName$>> $eventData.clientName$;
+/*END_SERVICE_CLIENT*/
+```
+
+**Moved to start()** in `template_skill/src/TemplateSkill.cpp`:
+```cpp
+// Service client creation now in start(), not in event callback
+$eventData.nodeName$ = rclcpp::Node::make_shared(m_name + "SkillNode$eventData.functionName$");
+$eventData.clientName$ = $eventData.nodeName$->create_client<...>($eventData.serverName$);
+
+// Service availability check with timeout at startup
+bool wait_succeded{true};
+int retries = 0;
+while (!$eventData.clientName$->wait_for_service(std::chrono::seconds(1))) {
+    if (!rclcpp::ok() || retries++ == SERVICE_TIMEOUT) {
+        wait_succeded = false;
+        break;
+    }
+}
+if (!wait_succeded) {
+    std::exit(1);  // Fail fast if service unavailable
+}
+```
+
+**New data field** in `include/Data.h`:
+```cpp
+std::string serviceClientH;  // Template for service client header declarations
+```
+
+**New replacer handling** in `src/Replacer.cpp`:
+```cpp
+std::string serviceClientH = savedCode.serviceClientH;
+replaceCommonEventPlaceholders(serviceClientH, eventData);
+writeAfterCommand(str, "/*SERVICE_CLIENTS_LIST*/", serviceClientH);
+```
+
+---
+
+### 4. Blackboard/Service Type Name Fix
+
+**Commit:** `e3f26a5` | **Date:** 2025-09-16 | **Type:** BUG FIX
+
+#### Problem
+When using blackboard interfaces (e.g., `blackboard_interfaces/GetIntBlackboard`), the generated code was incorrectly using the function name instead of the service type name for ROS2 service client templates.
+
+#### Solution
+Added separate `serviceTypeName` field to properly distinguish between the function being called and the interface type.
+
+#### Code Changes
+
+**New fields** in `include/Data.h`:
+```cpp
+std::string serviceTypeName;           // e.g., "GetIntBlackboard"
+std::string serviceTypeNameSnakeCase;  // e.g., "get_int_blackboard"
+```
+
+**Extraction logic** in `src/ExtractFromXML.cpp`:
+```cpp
+size_t lastSlash = eventData.messageInterfaceType.find_last_of("/");
+if (lastSlash != std::string::npos) {
+    eventData.serviceTypeName = eventData.messageInterfaceType.substr(lastSlash + 1);
+    turnToSnakeCase(eventData.serviceTypeName, eventData.serviceTypeNameSnakeCase);
+}
+```
+
+**Template fix** in `template_skill/src/TemplateSkill.cpp`:
+```cpp
+// Changed from (incorrect - used function name):
+std::shared_ptr<rclcpp::Client<$eventData.interfaceName$::srv::$eventData.functionName$>>
+
+// To (correct - uses service type):
+std::shared_ptr<rclcpp::Client<$eventData.interfaceName$::srv::$eventData.serviceTypeName$>>
+```
+
+---
+
+## Commit History (Chronological)
+
+| Date | Commit | Type | Summary |
+|------|--------|------|---------|
+| 2025-09-10 | `c5e885f` | fix | Wrong expected topic name in battery level skill |
+| 2025-09-10 | `18302c1` | fix | Topic name parsing for multi-part names |
+| 2025-09-11 | `a978d99` | fix | Correct component topic name |
+| 2025-09-11 | `a205446` | fix | Topic callback generation |
+| 2025-09-11 | `3ffe328` | fix | `msg_.x` → `_event.data.x` translation |
+| 2025-09-11 | `4cb8a93` | fix | Field type handling in responses |
+| 2025-09-11 | `ed7ee75` | fix | checkIfStartSkill test |
+| 2025-09-16 | `e3f26a5` | fix | Blackboard/service type names |
+| 2025-09-16 | `9905d7e` | fix | HL SCXML naming issues |
+| 2025-09-16 | `2509e9a` | fix | Minor HL SCXML fixes |
+| 2025-09-16 | `41505ca` | fix | **Segfault for unused services** |
+| 2025-09-17 | `7c684eb` | fix | **Data types from SCXML not interface files** |
+| 2025-09-30 | `37a62bd` | fix | interfaceResponseFields lookup |
+| 2025-10-01 | `3b1862b` | **feat** | **Data type mapping via location attribute** |
+| 2025-10-02 | `5d87317` | fix | Remove Python code leftover (930 lines) |
+| 2025-11-24 | `f0ad936` | fix | **Service client init in skill start** |
+| 2025-11-25 | `d24bc2b` | fix | Service client list in header |
+
+---
+
+## Files Most Affected
+
+| File | Changes | Purpose |
+|------|---------|---------|
+| [src/Replacer.cpp](src/Replacer.cpp) | 7 commits | Code generation and template substitution |
+| [src/ExtractFromXML.cpp](src/ExtractFromXML.cpp) | 6 commits | SCXML parsing and data extraction |
+| [template_skill/src/TemplateSkill.cpp](template_skill/src/TemplateSkill.cpp) | 4 commits | Skill template for ROS2 generation |
+| [include/ExtractFromXML.h](include/ExtractFromXML.h) | 3 commits | Parser function declarations |
+| [include/Data.h](include/Data.h) | 3 commits | Data structures for extracted information |
+